Ultra-small form factor optical connector and adapter

ABSTRACT

An optical connector holding two or more LC-type optical ferrules is provided. The optical connector includes an outer body, an inner front body accommodating the two or more LC-type optical ferrules, ferrule springs for urging the optical ferrules towards a mating receptacle, and a back body for supporting the ferrule springs. The outer body and the inner front body are configured such that four LC-type optical ferrules are accommodated in a small form-factor pluggable (SFP) transceiver footprint or eight LC-type optical ferrules are accommodated in a quad small form-factor pluggable (QSFP) transceiver footprint. A mating receptacle (transceiver or adapter) includes internal alignment slots configured to accept a corresponding alignment key on connector outer housing to ensure alignment and orientation for maximum signal transfer between opposing ferrule end faces.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCTUS1913861 filed Jan. 16, 2019,which is a continuation-in-part of U.S. patent application Ser. No.16/194,325, entitled ULTRA-SMALL FORM FACTOR OPTICAL CONNECTOR HAVINGDUAL ALIGNMENT KEYS and filed on Nov. 17, 2018, and U.S. patentapplication Ser. No. 16/103,555, entitled ULTRA-SMALL FORM FACTOROPTICAL CONNECTORS USING A PUSH-PULL BOOT RECEPTACLE RELEASE and filedon Aug. 14, 2018, each of which is a continuation-in-part of U.S. patentapplication Ser. No. 16/035,691, entitled ULTRA-SMALL FORM FACTOROPTICAL CONNECTORS and filed on Jul. 15, 2018, which claims priority toU.S. Provisional Patent Application No. 62/588,276, entitled MicroOptical Connectors and filed on Nov. 17, 2017, U.S. Provisional PatentApplication No. 62/549,655, entitled Grouped Mini Fiber Optic Connectorsand filed on Aug. 24, 2017, and U.S. Provisional Patent Application No.62/532,710, entitled Grouped Mini CS Fiber Optic Connectors and filed onJul. 14, 2017, each of which is hereby expressly incorporated byreference in its entirety.

FIELD

The present disclosure relates generally to ultra-small form factoroptical connectors and adapters.

BACKGROUND

The prevalence of the Internet has led to unprecedented growth incommunication networks. Consumer demand for service and increasedcompetition has caused network providers to continuously find ways toimprove quality of service while reducing cost.

Certain solutions have included deployment of high-density interconnectpanels. High-density interconnect panels may be designed to consolidatethe increasing volume of interconnections necessary to support thefast-growing networks into a compacted form factor, thereby increasingquality of service and decreasing costs such as floor space and supportoverhead. However, room for improvement in the area of data centers,specifically as it relates to fiber optic connections, still exists. Forexample, manufacturers of connectors and adapters are always looking toreduce the size of the devices, while increasing ease of deployment,robustness, and modifiability after deployment. In particular, moreoptical connectors may need to be accommodated in the same footprintpreviously used for a smaller number of connectors in order to providebackward compatibility with existing data center equipment. For example,one current footprint is known as the small form-factor pluggabletransceiver footprint (SFP). This footprint currently accommodates twoLC-type ferrule optical connections. However, it may be desirable toaccommodate four optical connections (two duplex connections oftransmit/receive) within the same footprint. Another current footprintis the quad small form-factor pluggable (QSFP) transceiver footprint.This footprint currently accommodates four LC-type ferrule opticalconnections. However, it may be desirable to accommodate eight opticalconnections of LC-type ferrules (four duplex connections oftransmit/receive) within the same footprint.

In communication networks, such as data centers and switching networks,numerous interconnections between mating connectors may be compactedinto high-density panels. Panel and connector producers may optimize forsuch high densities by shrinking the connector size and/or the spacingbetween adjacent connectors on the panel. While both approaches may beeffective to increase the panel connector density, shrinking theconnector size and/or spacing may also increase the support cost anddiminish the quality of service.

In a high-density panel configuration, adjacent connectors and cableassemblies may obstruct access to the individual release mechanisms.Such physical obstructions may impede the ability of an operator tominimize the stresses applied to the cables and the connectors. Forexample, these stresses may be applied when the user reaches into adense group of connectors and pushes aside surrounding optical fibersand connectors to access an individual connector release mechanism withhis/her thumb and forefinger. Overstressing the cables and connectorsmay produce latent defects, compromise the integrity and/or reliabilityof the terminations, and potentially cause serious disruptions tonetwork performance.

While an operator may attempt to use a tool, such as a screwdriver, toreach into a dense group of connectors and activate a release mechanism,adjacent cables and connectors may obstruct the operator's line ofsight, making it difficult to guide the tool to the release mechanismwithout pushing aside the adjacent cables. Moreover, even when theoperator has a clear line of sight, guiding the tool to the releasemechanism may be a time-consuming process. Thus, using a tool may not beeffective at reducing support time and increasing the quality ofservice.

SUMMARY OF THE INVENTION

An optical connector holding two or more LC-type optical ferrules isprovided. The optical connector includes an outer body, an inner frontbody accommodating the two or more LC-type optical ferrules, ferrulesprings for urging the optical ferrules towards a mating receptacle, anda back body for supporting the ferrule springs. The outer body and theinner front body are configured such that four LC-type optical ferrulesare accommodated in a small form-factor pluggable (SFP) transceiverfootprint or eight LC-type optical ferrules are accommodated in a quadsmall form-factor pluggable (QSFP) transceiver footprint. A matingreceptacle (transceiver or adapter) includes a receptacle hook and ahousing with an opening that accommodates the receptacle hook in aflexed position as the optical connector makes connection with themating receptacle by introducing the receptacle hook into an opticalreceptacle hook recess.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a prior art standard 6.25 mm pitch LCconnector SFP;

FIG. 1B is a perspective view of a prior art standard 6.25 mm pitch LCadapter;

FIG. 1C is a top view of the prior art adapter of FIG. 1B;

FIG. 1D is a front view of the prior art adapter of FIG. 1B, showing the6.25 mm pitch;

FIG. 2A is a perspective view of a prior art LC duplex connector;

FIG. 2B is a perspective view of a prior art LC duplex connector with aremote release pull tab;

FIG. 2C is a top view of a prior art LC connector used in theembodiments shown in FIGS. 2A and 2B;

FIG. 2D is a side view of the prior art LC connector of FIG. 2C;

FIG. 3 is an exploded view of one embodiment of a connector;

FIG. 4 is a perspective view of one embodiment of a connector;

FIG. 5 is a perspective view of one embodiment of a connector with theouter housing removed from the front body.

FIG. 6 is a perspective view of one embodiment of a duplex connector;

FIG. 7 is a perspective view of another embodiment of a duplexconnector;

FIG. 8 is a perspective view of one embodiment of a quad connector;

FIG. 9 is another perspective view of one embodiment of a quadconnector;

FIG. 10 shows various embodiments of adapter types;

FIG. 11A is a side view of a connector connected to an adapter;

FIG. 11B is a side view of a connector being removed from an adapter;

FIG. 12A is a side view of the outer housing of a connector beingremoved;

FIG. 12B is a perspective view of a transparent outer housing of aconnector showing the front body;

FIG. 13 is a perspective view of one embodiment of a quad connectorinserted into a corresponding adapter;

FIGS. 14A-C are illustrative examples of cable management using variousembodiments of connectors;

FIG. 15A-B are illustrative examples of cable management using multiplefiber strands per jacket;

FIG. 16 is an illustrative example of using a cable management systemusing multiple fiber strands per jacket.

FIG. 17 is another illustrative example of using a cable managementsystem using multiple fiber strands per jacket.

FIGS. 18A-B are various views of one embodiment of an MT-type connector.

FIG. 18C is a perspective of a lens-type ferrule.

FIGS. 19A-D are illustrative examples of possible alternative connectordesigns.

FIG. 20 shows moving two connectors from a duplex connector to twosimplex connectors.

FIG. 21A is an exploded view of a micro optical connector according toan embodiment.

FIG. 21B is a perspective view of the assembled micro optical connectorof FIG. 21A.

FIG. 21C is a perspective view of an assembled micro optical connectorhaving an alignment key on first side of the connector outer housing.

FIG. 22 is a front view of the micro optical connector of FIG. 21Bshowing overall connector dimensions and ferrule pitch.

FIG. 22A is a front view of the micro optical connector of FIG. 21Cshowing the dual alignment key locations and overall pitch or distancebetween the ferrules.

FIG. 22B is a front view another embodiment of FIG. 21C.

FIG. 22C is a perspective view of an adapter configured to accept a dualkey micro optical connector or connector of FIG. 21C according to thepresent invention.

FIG. 23A is a cross-sectional view of the micro optical connector ofFIG. 21B latched into the adapter of FIG. 24.

FIG. 23B is a cross-sectional view of the micro optical connectors ofFIG. 21B unlatched from the adapter of FIG. 24.

FIG. 24 is an exploded view of an adapter for the micro opticalconnectors of FIG. 21B.

FIG. 25A is a cross-sectional view of the adapter of FIG. 24, assembled.

FIG. 25B is a cross-sectional side view of the adapter housing of FIG.24.

FIG. 26 is a front view of the assembled adapter of FIG. 24.

FIG. 27A is an isometric view of the front body of the micro opticalconnector of FIG. 21A.

FIG. 27B is a right side view of the front body of FIG. 27A.

FIG. 28A is an isometric view of the back body of the micro opticalconnector of FIG. 21A.

FIG. 28B is a side view of the back body of FIG. 28A.

FIG. 29A is an isometric view of the outer housing of the micro opticalconnector of FIG. 21A.

FIG. 29B is a front view of the outer housing of FIG. 29A.

FIG. 29C is a cross-sectional view of the outer housing of FIG. 29Ashowing the top of an orientation protrusion.

FIG. 29D is an inner view of the outer housing of FIG. 29A;

FIG. 29E is an inner view of the outer housing of FIG. 29A.

FIG. 30 is a side view of an adapter hook of the adapter of FIG. 24.

FIG. 31 is an isometric view of the adapter of FIG. 24 assembled withthe micro optical connectors of FIG. 21B.

FIG. 32A is cross-sectional view of a prior art connector showing alatch gap.

FIG. 32B is a cross-sectional view of the micro optical connector ofFIG. 21B latched (left) and unlatched (right) within the adapter of FIG.24, assembled.

FIG. 33A depicts the micro optical connector of FIG. 21B in a QSFPfootprint, depicting dimensions in millimeters.

FIG. 33B depicts the micro optical connectors of FIG. 21B in an SFPfootprint, depicting dimensions in millimeters.

FIG. 34A-34C depicts adapter hooks interacting with the micro opticalconnectors of FIG. 21B before (FIG. 34A), during (FIG. 34B), and after(FIG. 34C) latching.

FIG. 35A-FIG. 35C depicts the micro optical connector of FIG. 21B sideflap operation before (FIG. 35A), during (FIG. 35B), and after (FIG.35C) latching.

FIG. 36A depicts plural micro optical connectors in a transceiver.

FIG. 36B is a front view of the transceiver of FIG. 36A.

FIG. 37 is an exploded view of a micro optical connector according to afurther embodiment.

FIG. 38 is an isometric view of a front body of the micro opticalconnector of FIG. 37.

FIG. 39 is an isometric view of a back body of the micro opticalconnector of FIG. 37.

FIGS. 40A, 40B, and 40C depict a technique for reversing polarity of theoptical connector of FIG. 37.

FIG. 41 is an exploded view of a micro optical connector according to afurther embodiment.

FIG. 42A is an isometric view of the front body of the micro opticalconnector of FIG. 41.

FIG. 42B is a side view of the front body of FIG. 42A.

FIG. 43 is an isometric view of the back body of the micro opticalconnector of FIG. 41.

FIGS. 44A, 44B, and 44C are isometric views of the outer housings thatmay be used with any of the micro optical connectors of FIGS. 21A, 37,and 41.

FIG. 45 is an exploded view of an adapter according to a furtherembodiment.

FIG. 46 is a cross-section of the adapter of FIG. 45, assembled.

FIG. 47 is an exploded view of a connector according to anotherembodiment.

FIG. 48 is an isometric view of the back body and the back post of theconnector of FIG. 47.

FIG. 49 is a cross-section of the back post of FIG. 47 assembled withoptical fibers.

FIG. 50 is a front view of the connector of FIG. 47.

FIG. 51 is an isometric view of the boot of the connector of FIG. 47.

FIG. 52 is a front view of the adapter of FIG. 45.

FIG. 53 is perspective view of a connector similar to the connector ofFIG. 47 but incorporating a push/pull release feature.

FIG. 53A is a side elevation of the connector of FIG. 53.

FIG. 53B is an end elevation of the connector of FIG. 53.

FIG. 54 is an exploded view of FIG. 53 connector.

FIG. 55 is a side perspective view of connector of FIG. 53 with an outerhousing removed.

FIG. 56 is a cross-section view of connector of FIG. 53 latched into areceptacle.

FIG. 57 is a cross-section view of connector of FIG. 53 partiallyremoved using push/pull release boot according to the present invention.

FIG. 58 is a cross-section view of connector of FIG. 53 released fromreceptacle inner latches or hooks of FIG. 24.

FIG. 59A is a side elevation of another embodiment of a connector.

FIG. 59B is an end elevation of the connector of FIG. 59A.

FIG. 60A is a perspective of another embodiment of an adapter.

FIG. 60B is an end elevation of the adapter of FIG. 60A.

FIG. 60C is a cross section taken in the plane of line 60C-60C of FIG.60B.

FIG. 61A is a perspective of another embodiment of an adapter.

FIG. 61B is an end elevation of the adapter of FIG. 61A.

FIG. 61C is a cross section taken through line 61C-61C of FIG. 61B.

FIG. 61D is a cross section taken in the plane of line 61D-61D of FIG.61C.

FIG. 62 is an elevation of another embodiment of an adapter with four ofthe connectors of FIGS. 59A and 59B installed therein.

FIG. 63 is an elevation of another embodiment of an adapter with two ofthe connectors of FIG. 59 installed therein.

FIG. 64 is an elevation of four of the connectors of FIGS. 59A and 59Barranged in side-by-side relation and superimposed to scale on a quadsmall form factor pluggable transceiver footprint.

FIG. 65 is an elevation of two of the connectors of FIGS. 59A and 59Barranged in side-by-side relation and superimposed to scale on a smallform factor pluggable transceiver footprint.

FIG. 66 is an elevation of four MT-type connectors arranged inside-by-side relation and superimposed to scale on a quad small formfactor pluggable transceiver footprint.

FIG. 67 an elevation of two MT-type connectors arranged in side-by-siderelation and superimposed to scale on a small form factor pluggabletransceiver footprint.

FIG. 68 is an elevation of another embodiment of an adapter with fourMT-type-ferrule connectors installed therein.

FIG. 69 is an elevation of another embodiment of an adapter with twoMT-type-ferrule connectors installed therein.

FIG. 70A is an elevation of another embodiment of an adapter.

FIG. 70B is perspective of the adapter of FIG. 70A shown in longitudinalcross section.

FIG. 71A is an elevation of another embodiment of an adapter.

FIG. 71B is perspective of the adapter of FIG. 71A shown in longitudinalcross section.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

This disclosure is not limited to the particular systems, devices andmethods described, as these may vary. The terminology used in thedescription is for the purpose of describing the particular versions orembodiments only, and is not intended to limit the scope.

As used in this document, the singular forms “a,” “an,” and “the”include plural references unless the context clearly dictates otherwise.Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art. Nothing in this disclosure is to be construed as anadmission that the embodiments described in this disclosure are notentitled to antedate such disclosure by virtue of prior invention. Asused in this document, the term “comprising” means “including, but notlimited to.”

The following terms shall have, for the purposes of this application,the respective meanings set forth below.

A connector, as used herein, refers to a device and/or componentsthereof that connects a first module or cable to a second module orcable. The connector may be configured for fiber optic transmission orelectrical signal transmission. The connector may be any suitable typenow known or later developed, such as, for example, a ferrule connector(FC), a fiber distributed data interface (FDDI) connector, an LCconnector, a mechanical transfer (MT) connector, a square connector (SC)connector, a CS connector, or a straight tip (ST) connector. Theconnector may generally be defined by a connector housing body. In someembodiments, the housing body may incorporate any or all of thecomponents described herein.

A “fiber optic cable” or an “optical cable” refers to a cable containingone or more optical fibers for conducting optical signals in beams oflight. The optical fibers can be constructed from any suitabletransparent material, including glass, fiberglass, and plastic. Thecable can include a jacket or sheathing material surrounding the opticalfibers. In addition, the cable can be connected to a connector on oneend or on both ends of the cable.

An “adapter” as used herein refers to any device that defines areceptacle for receiving an optical connector at least at one end andthat is configured to make an optical connection of the opticalconnector(s) received in the receptacle to an optical communicationdevice (e.g., another optical connector, a bare or sheathed opticalfiber, an optical device, an optoelectronic device, etc.) on the otherend of the adapter. Hence, for purposes of this disclosure, “adapter”includes two-sided adapters that have mating receptacles for opticalconnectors at opposite ends of the adapter, as well as transceivers thatdefine a single receptacle at one end to facilitate a connection of anoptical connector in the receptacle to another type of opticalcommunication device at the opposite end of the transceiver.

Various embodiments described herein generally provide a remote releasemechanism such that a user can remove cable assembly connectors that areclosely spaced together on a high density panel without damagingsurrounding connectors, accidentally disconnecting surroundingconnectors, disrupting transmissions through surrounding connectors,and/or the like. Various embodiments also provide narrow-pitch LC duplexconnectors and narrow-width multi-fiber connectors, for use, forexample, with future narrow-pitch LC SFPs and future narrow width SFPs.The remote release mechanisms allow use of the narrow-pitch LC duplexconnectors and narrow-width multi-fiber connectors in dense arrays ofnarrow-pitch LC SFPs and narrow-width multi-fiber SFPs.

FIG. 1A shows a perspective view of a prior art standard 6.25 mm pitchLC connector SFP 100. The SFP 100 is configured to receive a duplexconnector and provides two receptacles 102, each for receiving arespective LC connector. The pitch 104 is defined as the axis-to-axisdistance between the central longitudinal axes of each of the tworeceptacles 102. FIG. 1B shows a perspective view of a prior artstandard 6.25 mm pitch LC adapter 106. The adapter 106 is alsoconfigured to receive a duplex connector, and provides two receptacles108, each for receiving a respective LC connector. FIG. 1C is a top viewof the adapter 106 of FIG. 1B. The pitch of the adapter 106 is definedsimilarly to that of the SFP 100, as the axis-to-axis distance betweenthe central longitudinal axes of each of the two receptacles 108, asillustrated in FIG. 1D, which shows a front view of the adapter 106.

FIG. 2A shows a prior art LC duplex connector 200 that may be used withthe conventional SFP 100 and the conventional adapter 106. The LC duplexconnector 200 includes two conventional LC connectors 202. FIG. 2B showsanother prior art LC duplex connector 204 having a remote release pulltab 206, and including two conventional LC connectors 208. As shown, theremote release pull tab includes two prongs 210, each configured tocouple to the extending member 212 of a respective LC connector 208.FIGS. 2C and 2D show top and side views, respectively, of theconventional LC connector 208, having a width of 5.6 mm, and furthershowing the extending member 212.

As discussed herein, current connectors may be improved by variousmeans, such as, for example, reducing the footprint, increasing thestructural strength, enabling polarity changes, etc. Various embodimentsdisclosed herein offer improvements over the current state of the art,as will be further discussed below.

In some embodiments, as shown in FIG. 3, a connector 300 may comprisevarious components. Referring to FIG. 3, an illustrative embodiment of aconnector 300 is shown in an exploded view to display detail. In someembodiments, and as discussed further herein, a connector 300 may havean outer housing 301, a front body 302, one or more ferrules 303, one ormore ferrule flanges 304, one or more springs 305, a back body 306, aback post 307, a crimp ring 308, and a boot 309. In some embodiments,the back body 306 may comprise one or more protrusions 306.1 which mayinterlock with a window/cutout 302.1 in the front body 302. This mayallow for the back body 306 and the front body 302 to be securelyfastened together around the ferrule(s) 303, ferrule flange(s) 304, andthe spring(s) 305. The elements of FIG. 3 are configured such that twooptical connectors having four LC-type optical ferrules may beaccommodated in a small form-factor pluggable (SFP) transceiverfootprint or at least two optical connectors having a total of eightLC-type optical ferrules may be accommodated in a quad small form-factorpluggable (QSFP) transceiver footprint.

Referring now to FIG. 4, an embodiment is shown wherein the connector400 is assembled. In some embodiments, the assembled connector may havean outer housing 401, a front body 402 positioned within the outerhousing, one or more ferrules 403, one or more ferrule flanges (notshown), one or more springs (not shown), a back body 406, a back post(not shown), a crimp ring (not shown), a boot 409, and a push-pull tab410. In some embodiments, the connector may have one or more latchingmechanisms made up of a window 412 on the outer housing 401 near thepush-pull tab 410 and a protrusion 413 on the front body. The latchingmechanism made up of the window 412 and protrusion 413 securely attachesthe outer housing 401 to the front body 402. In a further embodiment,the outer housing 401 may have a recess 411 to receive a locking tab orlocking mechanism from an adapter (depicted in FIG. 13, below). Therecess 411 of the outer housing 401 is used to interlock with an adapter(depicted in FIG. 13, below) or transceiver receptacle to secure theconnector into the adapter. As would be understood by one skilled in theart, the push-pull tab 410 enables removal of the connector from areceptacle without requiring additional tools. Alternatively, thepush-pull tab may be eliminated and the connector removed manually. Inone or more further embodiments, the outer housing 401 may also have akey 414. The key 414 may keep the connector in a given orientation wheninserted into a receptacle such as an adapter or transceiver.

FIG. 5 depicts a procedure for changing the polarity of the opticalconnectors of the present disclosure. As shown in FIG. 5, in someembodiments, the latching mechanism of the connector 500 may be made upof two main parts: a window (not visible) and one or more protrusions513. As illustrated in FIG. 5, the outer housing 501 can slide on to orbe removed from the front body 502 by disengaging the latchingmechanisms formed by the protrusion 513 exiting through the window,whereby it contacts a rear wall of the window (refer to FIG. 4 for anillustrated example of the outer housing being attached to the frontbody via the latching mechanism). In some embodiments, the push-pull tab510 may be permanently attached to the outer housing 501, as shown.

The front body 502 may be removed from the outer housing 501, rotated180° as indicated by arrow 520, and re-inserted into the outer housing.This allows for a change in the polarity of the front body 502, as shownby the arrow diagram in FIG. 5, and therefore the ferrules can switchquickly and easily without unnecessarily risking the delicate fibercables and ferrules.

In some embodiments, it may be beneficial to connect two or moreconnectors together to increase structural integrity, reduce the overallfootprint, and cut manufacturing costs. Accordingly, as shown in FIG. 6,a connector 600 may in some embodiments, utilize an outer housing 601that is capable of holding two front bodies 602. Various otherembodiments are disclosed herein, and it should be noted that theembodiments disclosed herein are all non-limiting examples shown forexplanatory purposes only.

Accordingly, although the embodiment shown in FIG. 6 utilizes a duplexouter housing 601, additional or alternative embodiments may exist withmore capacity, for example, six or eight optical connectors within asingle outer housing. As shown in FIG. 6, in some embodiments, the outerhousing 601 may accept two front bodies 602, each with two separateferrules 603. As shown, the front body(s) 602 may securely fasten to theouter housing 601 via the latching mechanism 612 and 613. In additionalembodiments, the push-pull tab 610 may be modified, as shown, such thata single tab can be used to free the two or more connectors from anadapter. As illustrated in FIG. 6, the uni-body push-pull tab 610 andthe outer housing 601 may have two windows 612 with which to receivemultiple protrusions 613 of the front body(s) 602. As discussed hereinthe recesses 611 of the outer housing 601 are used to secure theconnectors to an adapter (depicted in FIG. 13 below). In one or morefurther embodiments, the connectors may have individual back bodies 606and boots 609 (i.e., one back body/boot per front body) as shown.

Alternatively, in some embodiments, such as that shown in FIG. 7, theconnector 700 may have a single boot 709 and a duplex (i.e., uni-body)back body 706 instead of individual back bodies (e.g., such as shown inFIG. 6). In some embodiments, the duplex back body 706 may havedifferent dimensions than that of the individual back bodies of FIG. 6,such as, for example, they may be longer to accommodate the need forrouting the fiber after it exits the boot 709. As with other embodimentsdiscussed herein, the connector shown in FIG. 7 may also include anouter housing (e.g., duplex outer housing) 701, one or more ferrules703, at least one latching mechanism formed by the protrusion (notshown) exiting through one or more windows 712, and a push-pull tab 710.

As stated, it may be beneficial to connect two or more connectorstogether to increase structural integrity, reduce the overall footprint,and cut manufacturing costs. Accordingly, similar to FIG. 6, FIG. 8shows a connector 800 that may, in some embodiments, utilize an outerhousing 801 that is capable of holding multiple (e.g., four) frontbodies 802.

As shown in FIG. 8, some embodiments may have an outer housing 801 ableto accept up to four front bodies 802, each with one or more ferrules803. As shown, each front body 802 may securely fasten to the outerhousing 801 via the latching mechanism 812 and 813. In additionalembodiments, the push-pull tab 810 may be modified such that a singletab can be used to remove the up to four connectors from an adapter. Asillustrated in FIG. 8, the push-pull tab 810 may include four recesses811, which as discussed herein are used to secure the connector to areceptacle such as an adapter (shown in FIG. 13, below) or the frontreceptacle portion of a transceiver. In one or more further embodiments,the connectors may have individual back bodies 806 and boots 809 (i.e.,one back body/boot per front body) as shown.

Similar to FIG. 8, FIG. 9 shows an embodiment where the outer housing901 is able to accept up to four front bodies 902, each with one or moreferrules 903. As shown, each front body 902 may securely fasten to theouter housing 901 via the latching mechanism 912 and 913. In additionalembodiments, the push-pull tab 910 may be modified such that a singletab can be used to remove the up to four CS connectors from an adapter.As illustrated in FIG. 9, the push-pull tab 910 may include fourrecesses 911, which as discussed herein are used to secure the connectorto an adapter (shown in FIG. 13, below) or the optical receptacleportion of a transceiver. The FIG. 9 embodiment may utilize a singleback body 906 and a single boot 909. In one or more further embodiments,the connectors may have individual back bodies 906 and boots 909 (i.e.,one back body/boot for all four front bodies) as shown.

In another aspect, the present disclosure provides method forreconfiguring optical cables in which the outer housings of theconnectors may be removed and the remaining portion of the assembledconnector is inserted into a housing having a larger or smallercapacity. For example, the outer housings of plural two-ferrule capacityhousings may be removed and the connector inner body and associatedcomponents inserted into a second outer housing that has either afour-ferrule or eight-ferrule capacity. Alternatively, an outer housingwith a four-ferrule capacity may be removed and the inner bodies andassociated components are inserted into two second outer housings, eachof the two second housings having a two-ferrule capacity. Similarly, anouter housing with an eight-ferrule capacity may be removed and replacedby two four-ferrule capacity housing or a four-ferrule capacity and twotwo-ferrule capacity housings. In this manner, cables may be flexiblyreconfigured to match the capacity of a mating optical-electricalcomponent such as a transceiver. This aspect of the present disclosureis demonstrated in connection with FIG. 10.

Referring now to FIG. 10, various embodiments may exist such as a singlehousing 1001 which receives a single connector 1002. Additionalembodiments may also exist, such as a duplex housing 1003 which receivestwo connectors 1004 and/or a quad housing 1005 which may receive up tofour connectors 1006. It should be understood by one skilled in the artthat various other embodiments may exist that are not explicitly shown.For example, a housing with the capacity for 5, 6, 7, 8, 9, 10 or moreconnectors may be utilized for various embodiments disclosed herein. Asshown below, it is desirable to have flexible housing configurations sothat connectors may be grouped and ungrouped between optical andoptoelectronic components such as adapters and transceivers.

Alternatively, in some embodiments the connector may utilize one or moreduplex back bodies with a single boot, similar to that shown in FIG. 7.Thus, similar to FIG. 7, an embodiment may allow for a further reducedfootprint, less cabling, and easier maintenance of the connector.Accordingly, one or more embodiments may have an outer housing that mayaccept up to four front bodies, each with one or more ferrules. In someembodiments, each front body may securely fasten to the outer housingvia a latching mechanism. In additional embodiments, the push-pull tabmay be modified such that a single tab can be used to free the up tofour front bodies from an adapter. The push-pull tab may include fouropenings with which to receive multiple locking tabs of the outerhousing. As discussed herein the locking tabs of the outer housing areused to secure the connectors to an adapter (shown in FIG. 13) or theoptical receptacle portion of a transceiver.

In further embodiments, the connector may utilize a single uni-body backbody with a single boot (i.e., as shown in FIG. 9). Thus, an embodimentmay allow for a further reduced foot print, less cabling, and easiermaintenance of the connector. Accordingly, one or more embodiments mayhave an outer housing that may accept up to four front bodies, each withone or more ferrules. Each front body may securely fasten to the outerhousing via the latching mechanism as discussed herein. In additionalembodiments, the push-pull tab may be modified such that a single tabcan be used to remove up to four connectors from an adapter. Thepush-pull tab may include four openings with which to receive multiplelocking tabs of the outer housing. As discussed herein the locking tabsof the outer housing are used to secure the connectors to an adapter.

The optical connectors of the present disclosure are all configured tobe received in a receptacle. As used herein, the term “receptacle”relates generically to a housing that receives an optical connector. Areceptacle includes both optical adapters, that is, components that matetwo or more optical connectors, and transceivers, which include anoptical receptacle to hold connectors that are to communicate with anoptoelectronic component (e.g., a component that converts opticalsignals to electrical signals). As shown in FIG. 11A, in one embodiment1100A, the outer housing 1101 may comprise one or more recesses 1111. Asdiscussed and shown herein, the one or more recesses may allow for areceptacle 1114 to securely connect to the connector 1100A. Accordingly,in some embodiments, the receptacle 1114 may have a receptacle hook1115, which is flexible and can secure the connector 1100A into thereceptacle via latching onto the wall of the recess 1111, as shown. Thislatching takes place when the outer housing 1101 is pushed forward intothe receptacle. The sloped portions of the outer housing 1101 allow thereceptacle hook 1115 to slide up and over the front of the outer housingthereby securing the connector 1100A into the receptacle.

Additionally or alternatively, in some embodiments, such as that shownin FIG. 11B, a connector 1100B may be removed from a receptacle 1114 bypulling the connector away from the adapter as indicated by thedirectional arrow. In some embodiments, the force may be applied by auser via the push-pull tab 1110. Alternatively, when a push-pull tab isnot present, the connector may still be manually removed from areceptacle. As shown in FIG. 11B, as the connector 1100B is removed fromthe receptacle 1114, the flexible receptacle hooks 1115 separate andslide up the slope of the end of the connector and allow for removal ofthe connector from the receptacle.

Referring now to FIGS. 12A and 12B, as discussed herein and previouslyshown in FIG. 5, the front body 1202 can be removed from the outerhousing 1201. In some embodiments, a portion of the outer body 1201 canbe flexibly extended away from the front body 1202 as shown by thearrows in FIG. 12A. As discussed herein, in some embodiments, the frontbody 1202 may comprise a protrusion 1213 which interlocks with a window(not shown) on the outer housing 1201. Accordingly, when force isapplied to the outer housing 1201 in a manner that removes the one ormore protrusions 1213 from the one or more windows (not shown, see FIG.4), the front body 1202 may be removed from the outer housing.

Referring now to FIG. 13, an embodiment 1300 is shown in which theconnector (not shown in its entirety) is inserted into a receptacle suchas adapter 1314. In this specific non-limiting example, the connector issimilar to that shown in FIG. 8 (i.e., comprising four front bodies eachwith their own back body 1306 and boot 1309). However, unlike FIG. 8,the embodiment shown here utilizes four individual push-pull tabs 1310instead of a duplex push-pull tab system which manipulates two latchingtabs per push-pull tab to allow the connector to be removed from theadapter 1314.

Various benefits and details have been discussed herein with regard tothe connectors and their modular ability (e.g., to include multipleconnectors into a single housing). In addition to the reduced footprint,structural improvements, and cost reduction, various embodiments hereinmay also be beneficial with regard to reducing the burden of cabling ina data center environment. Illustrative embodiments shown in FIGS. 14Athrough 14C depict cable configurations that may be used to reduce thecomplexity of optical cables in a compact environment. Note that any ofthe optical connectors described in this disclosure may be used in theseembodiments, including the optical connectors of FIGS. 21B, 37, and 41,to be discussed in detail below. FIG. 14A shows two duplex cablessimilar to the cable shown in FIG. 6. In some embodiments, one or moredetachable clips 1401 may be attached to two or more zip cables toprevent the zip cables from detaching. This allows for two or morecables to be bundled and reduce the risk of entanglement with additionalcables. FIG. 14B is an illustrative example of how easily an embodimentcan separate into two individual connectors by unbinding the cables andthus quickly and easily creating two independent fiber optic channelsthat can move and be connected independently. FIG. 14C shows anembodiment in which a duplex connector like that of FIGS. 6 and 14A isconnected to two separate individual connectors. Through the variablehousing configurations depicted above in FIG. 10, the cable of FIG. 14Acan be reconfigured as the cables of either 14B or FIG. 14C.

In addition to binding existing fiber cables, some embodiments hereinmay utilize a new four fiber zip cable. Referring now to FIG. 15A, aconventional zip cable (i.e., one with a single fiber strand 1520 perjacket 1521) is shown in comparison with an embodiment in which twofibers 1522 per jacket 1523 are utilized. It should be understood thatthis is merely a non-limiting example. In some embodiments, multiplefibers may be included per jacket, such as, for example, four fibers perjacket in order to utilize the single boot 909 and uni-body rear body906 of the connector shown in FIG. 9.

A specific example using multi-strand cables is shown in FIG. 16 forillustrative purposes only. It should be understood that numerousalternatives and modifications are possible, such as, for example, thatshown in FIGS. 18A-18B and FIGS. 19A-19D. As shown, a switch (e.g., 100Gswitch) 1630 is shown with a transceiver (e.g., 100G transceiver) 1631.The transceiver 1631 has a receptacle to receive duplex connectors 1632.From each of the two duplex connectors 1632, a four fiber cable 1633extends to connect to various other connectors and transceivers. In someembodiments, as discussed herein, a clip (e.g., detachable clip) 1640may connect two or more cables (e.g., 1633) to ensure the zip cables donot come apart. As shown, one four fiber cable 1633 is split into twotwo-fiber cables 1634, which are then each attached to a single simplexconnector 1635 and placed into a transceiver (e.g., 25G transceiver)1636. As further shown, one of the four fiber cables 1637 is connectedto a single duplex connector 1638, which is then inserted into anothertransceiver (e.g., 50G transceiver) 1639.

An additional or alternative embodiment is shown in FIG. 17. As shown,one or more switches (e.g., 400G switches) 1730 and 1732 are shown eachwith a transceiver (e.g., 400G transceiver) 1731 and 1733. The firsttransceiver 1731 has a receptacle that is receiving two simplex (single)connectors 1734 and one duplex (dual) connector 1735. From each of thetwo simplex connectors 1734, a two fiber cable 1736 extends to connectto various other connectors and transceivers. Similar to FIGS. 14 and16, some embodiments may have a clip (e.g., detachable clip) 1740 thatmay connect two or more cables (e.g., 1736, 1738, etc.) to ensure thezip cables do not come apart. From the duplex connector 1735 afour-fiber cable 1737 is split into two two-fiber cables 1738, which arethen each attached to a single simplex connector each and placed into atransceiver (e.g., 400G transceiver).

Accordingly, embodiments described herein allow for improvements overthe current state of the art. By way of specific example, connectorsgenerally have three types of fixed cables. Moreover, some cables may bebifurcated. As such, the cable cannot be split once installed and thepolarity of the cables cannot be changed. Alternatively, the embodimentsdiscussed herein may allow a user to change from a four-way to a2-Duplex, to a 4-simplex connector, etc. (e.g., FIG. 20). Moreover, asdiscussed herein, the individual connectors can be split into individualconnectors anytime, even after deployment. Additionally, the polaritycan be changed within the connectors easily in a manner that does notrisk damage to the one or more ferrules and fibers, as discussed above.It should also be noted that the depicted connectors are used hereinmerely for illustrative purposes, and that various other connectors maybe used in any embodiment (e.g., an MT connector, such as that shown inFIGS. 18A-18B, and the optical connectors of FIGS. 21, 37, and 41).

FIGS. 18A-18B depict an optical connector including an MT ferrule 1810in a housing that is substantially similar to the housing 301 of FIG. 3.As with the embodiment of FIG. 3, the various features of the connectorare configured such that two optical connectors having two MT-typeoptical ferrules may be accommodated in a small form-factor pluggable(SFP) transceiver footprint or at least four optical connectors having atotal of four MT-type optical ferrules may be accommodated in a quadsmall form-factor pluggable (QSFP) transceiver footprint. As will beappreciated by those skilled in the art, in one or more embodiments, anMT-type ferrule is a ferrule comprising a ferrule body having widthspaced apart between opposite ends, a pair of guide pin openings, and aplurality of optical fiber 1810 a-1810 d passages, as shown in FIG. 18B,spaced apart between the pair of guide pin openings. FIG. 18C is alens-type MT-type or mechanical transfer ferrule 1800 with an opening1810 e to receive epoxy to secure optical fibers within ferrule body1810 d. A plurality of optical fibers 1810 a-18101 are along a dimensionof ferrule body 1810 d at a proximal end. An opposing pair of guide pin1810 c holes are located the proximal end. Lens ferrule 1810 is at aslight incline 1810 f, as opposed to the MT-type ferrule depicted inFIG. 18B.

FIGS. 19A-19D show alternative embodiments of the optical connectors ofFIG. 3 in which the push-pull tabs are not integrated with the opticalconnector housing. As seen in FIGS. 19A-19B, a push-pull tab 1930 is aseparable element from a connector housing. The push-pull tab 1930actuates a latch 1910 for inserting and extracting the connector from anadapter or transceiver. An alternative latching mechanism is depicted inFIGS. 19C-19D. Latch 1950 includes a notch that is actuated by push-pulltab 1960.

FIG. 20 depicts the disassembly of a four-connector housing (two duplexconnectors in a single housing) into two duplex connectors. This may beperformed in changing, for example, a connector as shown in FIG. 14A toa connector as shown in FIG. 14C. In FIG. 20, an optical connector 2000is depicted including a housing 2010 that houses two duplex connectors(four optical fibers). The housing 2010 is removed, leaving the twoduplex connectors 2020. Two housings 2030 are then provided and twoindividual duplex connectors 2040 are then created from the initialsingle housing connector 2000. This reconfigurable housing simplifiescable management, for example, when optical cables are interconnectedbetween lower-speed transceivers and higher-speed transceivers as seenin FIG. 16.

FIG. 21A depicts an embodiment of an optical connector 2100, shown inexploded view while 21B depicts the optical connector 2100 in anassembled view. Optical connector 2100 may include an outer housing2110, a front body 2115, one or more ferrules 2122, one or more ferruleflanges 2124, one or more springs 2125, a back body 2130, a back post2135, a crimp ring 2140, and a boot 2145. The outer housing 2110 mayinclude a longitudinal bore for accommodating the front body 2115 and aferrule assembly 2120, a connector alignment key 2105 used duringinterconnection, a connector flap 2103 and an optional pull tab 2107 tofacilitate removal of the connector 2100 when connected in a dense arrayof optical connectors. Optionally, the ferrules may be LC-type ferruleshaving an outer diameter of 1.25 mm.

In prior art optical connectors, an inner enclosed housing was used inplace of open front body 2115. Front body 2115 includes top and bottomportions but no sidewalls, termed “open sidewalls” in this embodiment.By using front body 2115, space occupied by the prior art inner housingsidewalls becomes available to increase the density of opticalconnectors within a given footprint, an advantage over prior artconnectors. It was determined that the outer housing 2110, combined withthe front body 2115, provided sufficient mechanical strength and ferruleprotection, advantageously providing the space for additional opticalconnectors. Removal of sidewalls increases available space by 1-2millimeters.

Note that, in this embodiment, the outer housing is configured to holdtwo optical ferrules 2122. Typically, two optical ferrules may be usedin a “transmit” and “receive” pairing of optical fibers, called a duplexconnector. However, the outer housing may be configured to hold more orfewer optical ferrules including a single optical ferrule, multiples ofsingle optical ferrules, or multiple pairs of optical ferrules,depending upon the application. Further, the front body 2115 may beremoved from the outer housing 2110 and the front body placed in alarger outer housing with other front bodies to form a larger opticalconnector in a manner to be discussed in more detail below. Inparticular, two front bodies may be used with a four-ferrule outerhousing or four front bodies may be used with an eight-ferrule outerhousing.

Turning to FIGS. 29A and 29B, isometric and front views of the outerhousing 2110 are shown. As seen in the front view of FIG. 29B and thecross-sectional view of FIG. 29C, connector orientation protrusions 2910are provided within the interior of the outer housing 2110. Connectorprotrusion 2910 is further seen in the inner view of the housing, FIG.29E. When the front body is inserted within the longitudinal bore 2101of outer housing 2110, the outer housing connector flap 2103 locks theouter housing 2110 to the front body 2115 in the following manner. Asthe front body 2115 is inserted into the outer housing 2110, the outerhousing locking surface 2114, best seen in FIG. 27C, engages theconnector orientation protrusion 2910, seen in an inside view of theouter housing in FIG. 29D, labelled as “Flap A”, flexing the connectorflap 2103 outwardly from the outer housing body 2110, depicted in theinset of FIG. 29C. The flap protrusion mating location is indicated as“mating place B” in FIG. 29D. Once the locking surface 2114 passesbeyond the orientation protrusion, the connector flap returns to itsoriginal position (FIG. 29A), and the protrusion 2910 engages lockingsurface 2114 and any withdrawal of the front body assembly from theouter housing 2110 is prevented as the proximal end face of theconnector flap 2103 is stopped by protrusion 2910.

FIGS. 35A-35C depict the sequence of operations to remove an assembledfront body from the outer housing in order to reverse polarity or toaggregate plural connectors in a multi-connector housing. To separatethe front body from the outer housing, the connector flap 2103 is flexedoutward using a finger or a tool, as depicted in FIG. 35B. Flexing theconnector flap 2103 outwardly causes the protrusion 2910 to disengagefrom the front body's outer housing locking surface 2114, permitting thefront body/ferrule assembly 2115 to be removed from the outer housing.This may be performed when it is desired to reverse the polarity of theconnector (to be discussed below) or when desiring to aggregate pluralconnectors into a larger connector housing as discussed above. Theseparated components are depicted in FIG. 35C, that is, front body 2115with the ferrule assembled therein and outer housing 2110.

In some embodiments, the back body 2130 may comprise one or moreprotrusions or hooks 2134, best seen in FIGS. 28A and 28B, which mayinterlock with a back body hook window/cutout 2119 in the front body2115. This may allow for the back body 2130 and the front body 2115 tobe securely fastened together around the ferrule(s) 2122, ferruleflange(s) 2124, and the spring(s) 2125. The back body 2130 includes acable bore 2820, spring guides 2132, and side protrusions 2810.

During assembly, the ferrule flanges 2124 fit into ferrule flangealignment slots 2117 (see FIGS. 27A and 27B) adjacent the ferruleopenings 2116 of the front body 2115, compressing the springs 2125(preload) which are positioned along front body spring holders 2118. Theends of the springs 2125 are secured on spring guides 2132 (FIGS. 28A,28B) of back body 2130 by spring tension. As seen in the assembledcross-sectional views of FIGS. 23A and 23B, the springs 2125 arepositioned to urge the ferrules 2122 into contact with mating connectorsor transceiver optics, ensuring minimum insertion loss. As further seenin FIGS. 27A and 27B, the front body includes a receptacle hook recess2710 with a receptacle hook retainer surface 2720 the receiver areceptacle hook when mating with an adapter or with a transceiverreceptacle, as shown in further detail below.

Further reductions in connector size may be obtained by reducing thesize of springs 2125, see FIG. 21. By using a maximum spring outerdiameter of 2.5 mm, the pitch of the ferrules, that is to say, thespacing between adjacent ferrules, may be reduced to 2.6 mm when coupledwith the removal of inner housing walls and walls separating adjacentferrules. This advantage is best seen in FIG. 22 which depicts the frontof connector 2100 showing overall connector dimensions and ferrulepitch. The connector size 4.2×8.96×30.85 mm (2207, 2006 respectively)(excluding optional pull tab 2107 and connector alignment key 2105) witha ferrule pitch of 2.6 mm 2205. FIG. 22A depicts connector 2100 with asecond alignment key 2105.1 positioned opposite a first alignment key2105. Also, alignment key 2105 width “W1” is greater than secondalignment key 2015.1 width “W2”. The difference in widths “W1” and “W2”ensures connector 2100 is correctly oriented in adapter port, oralternatively connector 2100 polarity, e.g. Tx, Rx location, matches anopposing pair of fibers on at a second port of adapter 2200.

FIG. 22B depicts alignment key 2105 offset from alignment key 2105.2.Instead of opposing alignment keys, as depicted in FIG. 22A, an offsetallows for manufacturing tolerances in internal alignment slots (2280a-2280 b, 2282 a-2282 b). Further offset of alignment key 2105.2 helpsprevent a user placing a first connector into internal alignment slot2280 a and slot 2282 b, due to the close proximity of a pair of opposingalignment slots. This may occur as connector 2100 is designed to besmaller and smaller to increase fiber connector density within anadapter 2200 with a standardized outside dimension. It is furtherunderstood, the corresponding internal alignment slot width is sized toaccept its corresponding alignment key, and can be no small than “W1” or“W2” for its respective alignment key (2105, 2105.1).

As best seen in FIG. 21B, the outer housing 2110 and the front body 2115together provide a receptacle hook ramp 2940 (on the outer housing) usedto guide a receptacle hook into a receptacle hook recess 2170 (in thefront body 2115), also shown in FIGS. 27A and 27B (receptacle hookrecess 2710 and receptacle hook retainer surface 2720). The receptaclehook, to be discussed in more detail below, may be from an adapter or atransceiver to secure the optical connector 2100 thereto. As seen inFIG. 21C, an alignment key 2105 is positioned on the outside ofconnector housing 2110 nearer the proximal end or ferrule end of theconnector. This allows earlier alignment of connector within adapterport. Alignment key 2105 allows a user to position connector 2100 withinan adapter port 2405 by aligning key 2105 with alignment slot 2403.

FIG. 22C depicts an adapter 2200 similar to FIG. 24 adapter 2400. FIG.22C adapter has at least one pair of alignments slots (2280 a, 2282 a).The slots (2280 a-2280 d; 2282 a-2282 d) may be opposing or slightlyoffset to accommodate a large number of connectors 2100, 2200A or 2200Bwith the adapter 2200, as described above in FIG. 22B. The opposingslots or substantially opposing alignment slots provide orientation of aconnector 2100, 2200A or 2200B inserted into adapter 2200. Connectors2100, 220A and 2200B may be mixed and matched and secured within adapter2200. Orientation also ensures correct mating polarity between opposingconnectors, that is, Tx1, Rx1 are opposite Tx2 and Rx2 respectively.Connector 2100 is inserted into an adapter port defined by slot pair(2282 a, 2280 a) while second connector 2200A or 2200B is inserted intoa second adapter port (2280 b, 2282 b). Likewise, connector 2200A may beinserted in each port, defined by opposing slots (2280 a, 2282 a) oropposing slots (2280 d, 2282 d). Alternatively, instead of connectors atopposing port side from (2280 a, 2282 a) transceiver 2300 may inserted.Transceiver 2300, as shown in FIG. 17, converts an optical signal into adigital signal, as is known in the prior art. The alignment keys on theconnector outer housing and the alignment slots help ensure properorientation to establish a communication channel, that is, fiber tofiber transfer of the light signal, while the alignments keys and slotsfurther help to ensure the opposing connectors end faces or ferrules arein the same parallel path to transmit light across the air gap betweenferrule to opposing ferrule most efficiently.

The optical connectors 2100 may be used in a variety of connectionenvironments. In some applications, the optical connectors 2100 willmate with other optical connectors. Typically, this mating will occurwith a receptacle such as an adapter or optical transceiver receptacle.An exemplary adapter 2400 depicted in FIG. 24 in an exploded view anddepicted in FIG. 31 having four mating pairs of optical connectors 2100latched therein. In other applications, as when an optical signal is tobe converted to an electrical signal, the micro optical connectors 2100will mate with an optical receptacle in a transceiver 3600 as shown inFIG. 36. Typically, transceiver 3600 may be found in a data center,switching center, or any other location where optical signals are to beconverted to electrical signals. Transceivers are often a part ofanother electrical device such as a switch or a server, as is known inthe art. Although much of the connection operation of this embodimentwill be described with respect to an adapter, 2400, it is understoodthat substantially similar mechanical retention mechanisms arepositioned within the receptacle of transceiver 3600 so that anydescription of connector retention in adapter 2400 applies in asubstantially similar way to retention of an optical connector withintransceiver 3600. An example of a transceiver optical receptacle isdepicted in FIG. 36B (holding optical connectors 2100); as seen in FIG.36B, the connection environment is substantially similar to one-half ofan adapter 2400.

Turning to FIG. 24, further size reductions in the overall opticalassembly of connectors plus adapter or connectors plus transceiver maybe obtained through various connection mechanisms to be described withrespect to the adapter 2400 but also apply to optical connectionfeatures within the front end of transceiver 3600. The adapter 2400includes an adapter housing 2402 having an adapter alignment assembly2430 positioned therein. The adapter alignment assembly 2430 includesalignment sleeves 2410 positioned within alignment sleeve openings 2440of alignment sleeve holders 2442. The adapter alignment assembly furtherincludes receptacle hooks 2302 that will grip optical connectors 2100through front body connector hook recess 2710 of FIG. 21B. As seen inFIG. 30, receptacle hooks 2302 include an inner surface 3110. Theadapter housing 2402 further includes connector alignment slots 2403that mate with connector alignment key 2105 of FIG. 21A. The connectors2100 are received through adapter port 2405 of the adapter housing 2402which also includes flex tab 2401, cutout 2456, mount plate 2452 andpanel hook 2490. To assemble the adapter alignment assembly 2430 in theadapter housing 2402, adapter housing hooks 2432 are provided. Adapterhousing hooks 2432 are received in housing adapter hook openings.

In one or more embodiments alignment slots 2403 are formed as part ofouter housing 2402. Slots 2403 extend through an entire thickness of awall portion housing 2402, as shown in FIG. 24. Alignment key 2105 isaccepted within slot 2403, thus allowing the overall dimension ofhousing 2402 to be smaller, as alignment key 2105 is not containedwithin or inside of the housing walls. FIG. 25A depicts a cut-away viewof adapter 2400 along longitudinal axis with slots or cut-outs 2403formed in adapter housing 2402. Slots receive alignment key 2105 locatedon either side of connector housing 2110. Latch hook 2302 is partiallylifted through opening 2420 upon insertion of connector into receptacle,as shown in FIGS. 34A-34 c. Alignment sleeve 2442 receives a LC typeferrule 2222 upon insertion of connector into adapter receptacleopening. Alignment key 2105 on connector ensures ferrule is receivedwithin alignment sleeve 2442 without ferrule tip engaging sleeve 2442walls causing damage to connector, thereby increasing insertion loss.FIG. 25B depicts similar cut-away as shown in FIG. 25A except onealignment sleeve 2442 is shown. The side opposite to alignment sleeve2442 can accept a transceiver 1636 fiber stub assembly as depicted inFIG. 16.

It should be understood that above description of connection mechanismswith respect to adapter 2400 may be applied in a substantially similarway with respect to the receptacle of transceiver 3600. Particularly,the receptacle of transceiver 3600 may include a receptacle housinghaving a receptacle alignment assembly positioned therein. Thereceptacle alignment assembly includes alignment sleeves positionedwithin alignment sleeve openings of alignment sleeve holders. Thereceptacle alignment assembly further includes receptacle hooks thatwill grip optical connectors 2100 through front body connector hookrecess 2710 of FIG. 21B. As seen in FIG. 30, receptacle hooks 2302include an inner surface 3110. The receptacle housing further includesconnector alignment slots that mate with connector alignment key of FIG.21A. The connectors 2100 are received through connector opening of thereceptacle housing which also includes flex tab, cutout, mount plate andpanel hook. To assemble the receptacle alignment assembly in thereceptacle housing, receptacle housing hooks are provided. Receptaclehousing hooks are received in housing receptacle hook openings.

To further reduce the size of optical connectors and associated matingcomponents, the adapter housing 2402 includes receptacle hook openings2420, seen in FIGS. 25A and 25B. Receptacle hook openings 2420accommodate the clearance required by receptacle hooks 2302 when theyflex upwards prior to latching with connectors 2100. The interaction ofthe receptacle hooks 2302, having slanted inner surfaces 3110, with thereceptacle hook openings 2420 is best seen in FIGS. 32B and 34A-C. Priorto latching (FIG. 34A), the receptacle hook 2302 is in an unflexedcondition within the receptacle (adapter or transceiver). As theconnector 2100 is inserted into the adapter housing 2402 or thetransceiver, the receptacle ramp 2490 pushes against the receptacle hookinner surfaces 3110, flexing receptacle hook 2302 into the receptaclehook opening 2420. Without providing the opening, additional clearancewould need to be provided to accommodate the flexing of the receptaclehook 2302. This additional required clearance is depicted in the priorart connector/adapter of FIG. 32A. As seen in FIG. 32A, a connectorlatch gap 3210 must be provided in the prior art to accommodate theprior art connector hooks, increasing the overall footprint of the priorart connector/adapter assembly. By providing receptacle hook openings2420 in the present disclosure, approximately 2.25 mm of valuablefootprint real estate is obtained which may be used to increaseconnector density. Hook 2302 has an adapter housing hook 2432. Referringto FIG. 34C, housing hook 2432 is secured behind a wall cut-out 2402 b.

Another improvement in adapter size is obtained by removing prior artadapter walls between adjacent connectors. This is best seen in thefront view of an assembled adapter 2400 shown in FIG. 26. As seen, pairsof ferrule alignment sleeves 2410 are separated only by connector gap2610 with a 4.35 mm pitch between adjacent connectors. The adapter sizeis 19.0×10.71×32.5 mm (excluding the adapter flange 2460). Also seen inFIG. 26 is the connector alignment slot 2403, alignment sleeve holder2442, and a front view of receptacle hooks 2302.

FIG. 31 depicts an assembled adapter 2400 with four pairs of matingconnectors 2100 latched therein. Note that in the latched position,receptacle hooks 2302 do not extend into receptacle hook openings 2420.This is further visible in the cross-sectional view of an assembledadapter 2400 of FIG. 25A. Connector alignment keys 2105 are positionedwithin connector alignment slots 2403. As seen in the cross-sectionalview of FIG. 23A, the push-pull tab 2017 may extend beyond the connectorboot 2145 providing clearance to easily grip the tab and remove aconnector. Also seen in FIG. 31 is adapter flex tab 2401 and panel hook2490 for interaction with racks or other equipment.

Through the various features described above, the density of opticalconnectors 2100 that may be provided in the standard transceiverfootprint connector spaces may be doubled. For example, in a small formfactor pluggable (SFP) footprint of 14×12.25 mm, two connectors 2100having four LC-type ferrules 2122 of 1.25 mm outer diameter may beaccommodated as seen in FIG. 33B. Similarly, in a quad small form factorpluggable (QSFP) footprint of 13.5×19 mm, four connectors 2100 having atotal of eight LC-type ferrules 2122 may be accommodated as seen in FIG.33A. Further, by providing the connectors in transmit and receive pairs,greater flexibility in optical routing is obtained, as demonstrated byprevious FIGS. 16 and 17.

Turning to FIG. 37, another embodiment of an optical connector isdepicted. In this embodiment, the last two digits of each elementcorrespond to the similar elements in the optical connector of FIG. 21Aet seq. In FIG. 37, connector 3700 may include an outer housing 3710, afront body 3715, one or more ferrules 3722, one or more ferrule flanges3724, one or more springs 3725, a back body 3730, a back post 3735, acrimp ring 3740 (depicted with an optional heat shrink tube extendingtherefrom), and a boot 3745. The outer housing 3710 may include alongitudinal bore 3701 for accommodating the front body 3715 andferrules 3722, a connector alignment key 3705 used duringinterconnection, a connector flap 3703 and an optional pull tab 3707 tofacilitate removal of the connector 3700 when connected in a dense arrayof optical connectors. Optionally, the ferrules may be LC-type ferruleshaving an outer diameter of 1.25 mm.

In FIG. 38 an isometric view of the front body 3715 is depicted. In thisembodiment, the back body hook cutout 3819 has been moved forward,advantageously strengthening the assembled connector in side loadenvironments. An alignment tab 3895 is provided for mating with areceiving recess on the back body. The receptacle hook recess 3910operates in a substantially similar manner to the recess of FIG. 21A,described above. A ferrule flange alignment slot 3817 is also provided.

In FIG. 39, the back body 3730 is depicted, showing alignment tab recess3997 for receiving alignment tab 3895. The front body hook 3934, forinterconnecting in back body hook cutout 3819, extends outwardly fromthe main portion of the back body through extended hook arm 3996.Through the extended hook arm 3996 and the alignment tab 3895, breakageduring side loads is reduced as the load is redistributed more evenlyacross the entire connector, reducing stress on the backpost.

As seen in FIGS. 40A-40C, the assembled front body 3715 may be removedfrom the outer housing 3710, rotated 180° as indicated by the arrow(FIG. 40B), and re-inserted into the outer housing (FIG. 40C). Thisallows for a change in the polarity of the front body 3715, andtherefore the ferrules can switch quickly and easily withoutunnecessarily risking the delicate fiber cables and ferrules. Asdescribed previously with respect to FIGS. 35A-35C, connector flap 3703is flexed outward to release the front body from the outer housing.

Turning to FIG. 41, another embodiment of an optical connector isdepicted. In this embodiment, the last two digits of each elementcorrespond to the similar elements in the micro optical connectors ofFIG. 21A and FIG. 37. In FIG. 41, connector 4100 may include an outerhousing 4110, a front body 4115, one or more ferrules 4122, one or moresprings 4125, a back body 4130, a crimp ring 4140, and a boot 4145. Theouter housing 4110 may include a connector flap 4103 and an optionalpull tab 4107 to facilitate removal of the connector 4100 when connectedin a dense array of optical connectors. Optionally, the ferrules may beLC-type ferrules having an outer diameter of 1.25 mm.

As seen in FIG. 42A, the front body 4015 in this embodiment includes amiddle wall 4260 interposed between the ferrules and springs when thefront body is assembled. This middle wall reduces the possibility of thesprings becoming entangled with each other, binding the connector andbreaking the optical fibers. The front body 4015 also includes analignment cut out guide 4625, seen in the side view of FIG. 42B. Thealignment cut out guides the back body 4030 into the front body 4015during assembly of the connecter, and also further reduces the side loadthat leads to connector breakage or disconnection of the front body andthe back body 4030.

Back body 4030, depicted in an enlarged view in FIG. 43, includes analignment guide 4377 that fits into the alignment cut out guide 4265 ofFIG. 42B. The wall structure 4378 also stops the front body to preventover-compressing the springs and provides strength under a side load.

Various modifications to the outer housing, depicted in FIGS. 44A-44C,may be used with any of the optical connectors depicted in FIGS. 21, 37,and 41 or earlier embodiments. In FIG. 44A, the push-pull tab 3707 mayinclude a release recess 4473. Release recess 4473 permits insertion ofa tool or fingernail to remove the connector from an adapter ortransceiver, without disturbing adjacent connectors. Similarly, FIG. 44Bdepicts a release hole 4499 in push-pull tab 3707 to permit insertion ofan extraction tool to remove the connector from an adapter ortransceiver. FIG. 44C shows a modified connector flap 3703 with anincreased cutout size of 1 mm to make it easier to insert a tool or afinger to flex the flap 3703 and remove the front body assembly whenmaking a polarity change or aggregating the front body with other frontbodies in a larger outer housing.

Another embodiment of an adapter/transceiver receptacle is depicted inFIG. 45. Unlabeled elements are substantially similar to elementsdepicted in FIG. 24. In this FIG., adapter housing hooks 4532 can beseen along with receptacle hooks 4502. Turning to the cross-sectionalview of the assembled adapter in FIG. 46, the engagement of theseelements may be seen. FIG. 46 shows adapter housing hooks 4532 securedbehind adapter wall portion to fix hook within adapter housing 2402.

Another embodiment of an optical connector 4700 is depicted in FIG. 47.The optical connector of FIG. 47 includes outer housing 4710, front body4715, ferrules 4722, springs 4725, back body 4730, backpost 4735, crimpring 4740, and boot 4745. Here, the emphasis is on the back body, 4730.A more detailed view of the back body 4730 is presented in FIG. 48. Inthis embodiment, the backpost flange has a substantially rectangularshape in order to narrow the overall connector profile by approximately0.5 mm. Back post overmolding 4859 accommodates the back post flange4857 and reduces the potential for back post breakage. The back wall4853 is extended in length to 3 mm from 1.5 mm to improve the sideloadstrength of the overall connector. The crimp ring positioning 4855 isinversed from earlier embodiments to improve holding of aramid fiberfrom an optical fiber cable, improving cable retention of the back post.

Many advantages are achieved by the backpost of FIG. 48. In addition toincreased connector strength, a longer fiber path 4901 is provided asshown in FIG. 49. This longer fiber path, approximately 1.5 mm longerthan in previous embodiments, allows for a gentler curve as the fibersare split from the fiber optic cable, improving insertion and returnloss of the fibers. In FIG. 49, the back wall 4853 can be seen as aportion of the back body 4730.

In view of the various modifications of this embodiment, FIG. 50 depictsa connector 4700 front view showing overall reduced connector width of3.85 mm. Such a size reduction permits 4 optical connectors (a total of8 ferrules) to be accommodated in a transceiver or connector footprintof 16 mm (including tolerances). Thus, the connectors of the presentinvention may be used to connect 8 LC-ferrule-housed fibers in a QSFPfootprint.

To further decrease the space required by the optical connectors, a sidethickness reduction may be carried out on the boot of connector 4700.Side thickness reduction 5103, depicted in FIG. 51, narrows thethickness of the boot on either side, reducing the space required by theboot to the 3.85 mm profile of connector 4700. Thus four connectors willfit in the QSFP transceiver footprint. This footprint is shown in theadapter front view of FIG. 52—as noted above, the front view of anadapter and that of a transceiver are substantially similar from theoptical perspective. In FIG. 52, the adapter inner wall is reduced from17.4 mm to 16 mm. All of the modifications set forth in the FIG. 47 etseq. embodiment make it possible for the four connectors to fit in theprofile of FIG. 52.

FIG. 53 depicts connector 5300 with a push/pull boot assembly 5345 a atits distal end receiving a fiber cable with a plural of fiber strandstherein, and a proximal end configured to connect and secure to a backbody 5330 secured with outer housing 5301. Outer housing 5301 has anopening 5301 a with a stop face 5301 b that boot wing (5545 b, 5545 c)(refer to FIG. 55) engages when boot assembly 5345 a is pulled in adistal direction fully to release connector 5300 from a receptacle asshown in FIG. 57.

FIG. 54 depicts an exploded view of connector 5300 of FIG. 53. Bootassembly 5345 a accepts crimp ring assembly 5440 a having a protectivetube 5440 c covering fiber strands and a crimp ring 5440 b secured to aback post 5430 c of back body 5330, which in one or more embodimentscomprises a back body member that is separately attached to the backpost. A pair of springs 5425 are placed over a corresponding ferruleassembly 5420 comprising a ferrule and ferrule flange. The ferruleassembly and springs are held within front body 5415 by back body 5330,as described for connector 2400. The front body 5415 is inserted into adistal opening of outer housing 5301 with boot assembly wing 5545 asecured with a distal opening 5301 a of outer housing.

FIG. 55 depicts connector of FIG. 53 without its outer housing 5301, inan assembled configuration. Boot assembly 5345 a is secured on back post5430 c of back body 5330 a via crimp ring 5440 a, as described in FIG.54. Wings (5545 b, 5545 c) secure FIG. 55 assembly within outer housing5301, and during release of connector 5300 from a receptacle, wings(5545 b, 5545 c) pull back outer housing a specific distance “d”, whichreleases hook 5625 that is seated in recess 5611 (refer to FIG. 56),while connector 5300 is secured within receptacle 2400.

FIG. 56 depicts connector 5300 secured within receptacle 2400 of FIG.24. Receptacle hook or latch 5625 rests in connector recess 5611 formedwithin front body 5615, at its proximal end. A gap of distance “d” 5629limits travel of outer housing 5601 as boot release 5645 a wings (5645b, 5545 b) engage 5301 b stop face of outer housing 5601. Crimp ring 564c is shown secured to back post 5630 c. Back body 5630 b is securedwithin front body 5615 distal openings 5451 b (FIG. 54). FIG. 56 furtherillustrates adapter housing hooks 5632 for connector hook 5625 securedbehind adapter housing wall cut-out portion 2402 b.

FIG. 57 depicts connector 5300 being removed or pulled out of receptacle2400 in direction “P”. Hook or latch 2425 within receptacle housinglifts out of recess 5711 along front body ramp 5401 d (FIG. 54), as bootassembly is being pulled rearward or in a distal direction. Gap 5529 isclosed as shown in FIG. 57. Inner face of connector housing 5715 c isflush with front face of front body 5701 e, which stops travel of bootassembly and is configured to ensure hook 2425 is displaced from recess5711 to release connector from receptacle, as shown in FIG. 58. FIG. 58depicts connector 5300 removed from receptacle 2400 using boot assembly5845 a. Wings (5845 b, 5845 c) are flush with outer housing face 5801 b.Spring 2825 bias forward front body face 5815 c to be flush with frontbody face 5801 e. Hook or latch 2425 is displaced from recess 5811, andhook resides in a gap 2400 a within outer housing of receptacle 2400.FIG. 58 further depicts adapter housing hook 2432 secured against wallportion 2402 b formed by gap 2400 a within adapter housing for a hook toflex into during connector insertion.

Accordingly, referring to FIGS. 53, 53A, 54, and 56, a low-profileoptical connector, generally indicated at 5300, is configured to beretained in the receptacle of an adapter by a receptacle hook. Anexemplary embodiment of an adapter to which the connector 5300 can bemated will be described in further detail below. In general, the opticalconnector 5300 comprises first and second recesses 5361, 5363 onopposite sides of the connector. For example, the first recess 5361 canbe configured to receive a portion of a first hook arm of a receptaclehook and the second recess 5363 can be configured to a portion of asecond hook arm of the receptacle hook to retain the optical connector5300 in the receptacle.

In the illustrated embodiment, the connector 5300 includes the outerhousing 5301 and a plurality of optical fibers 5365 (FIG. 53B) aresupported in the housing. Suitably, the optical fibers are locatedbetween the first and second recesses 5361, 5363. In one or moreembodiments, the recesses 5361, 5363 are spaced apart along a height HC(broadly, a first dimension) of the connector 5361, and at least some ofthe optical fibers 5365 are spaced apart along the same dimensionbetween the recesses. In the illustrated embodiment, the opticalconnector comprises two LC ferrules 5420 supporting the optical fibers.The ferrules 5420 are located between the recesses 5361, 5363 and spacedapart along the height HC of the connector 5300. In another embodiment,the LC ferrules 5420 are replaced with SC ferrules or one or moremechanical transfer (MT-type) ferrules (see FIGS. 18A, 18B) oriented sothat fibers are spaced apart along the height HC of the connector 5300.

As explained above in reference to FIGS. 56-58, the outer housing 5301of the connector 5300 is configured to be removably inserted into areceptacle of an adapter. The outer housing 5301 comprises an openingextending through the outer housing along a longitudinal axis LA (FIG.53A). At least one inner front body 5415 is received in the opening ofthe outer housing 5301 (see FIGS. 54, 55). The inner front body 5415 hasan interior 5367 in which the inner front body is configured to supportat least one optical fiber ferrule 5420, and in turn support a pluralityof optical fibers.

Referring to FIGS. 54 and 55, the inner front body 5415 comprises firstand second longitudinal wall portions 5369, 5371 extending along thelongitudinal axis LA on opposite ends of the interior. In theillustrated embodiment, the inner front body 5415 comprises an upperlongitudinal body portion 5369 and a lower longitudinal body portion5371 spaced apart along the height HC (first dimension) of the innerfront body. The inner front body 5415 further comprises a front endportion 5373 that extends along the height HC of the connector 5300adjacent the front end thereof. The front end portion 5373 connects thefront end section of the upper lower longitudinal body portion 5369 tothe front end section of the lower longitudinal body portion 5371. Thefront end portion 5369 suitably has one or more openings through whichferrules 5420 may extend and/or optical signals are passable from theoptical fibers 5365. The front end portion 5373 supports the upper andlower longitudinal body portions 5369, 5371 in spaced apartrelationship. Suitably, rear end portions of the upper and lowerlongitudinal body portion are not connected by any material. Inaddition, the inner front body 5415 has open sidewalls between the upperand lower wall portions 5369, 5371 on opposite sides of the interior5367. As explained above, the open sidewalls allow a plurality of theconnectors 5300 to be arranged side-by-side in relatively high densityarrangements.

In the illustrated embodiment, front end sections of the upper and lowerportions 5369, 5371 define the adapter hook recesses 5361, 5363. Therecesses are exposed through aligned openings 5377, 5379 (FIG. 54) inthe outer housing 5301 when the inner front body 5415 is installed inthe outer housing.

As explained above, a ferrule spring 5425 can be compressed between aflange of each ferrule 5420 and a back body 5330 that can be lockinglyengaged with one of the inner front body 5415 and the outer housing 5301to hold the inner front body and the ferrules in the outer housing.

Referring to FIGS. 53-53C, the outer housing comprises an alignment key5305 on the top side of the outer housing 5301. Referring to FIGS.59A-59B, in another embodiment of the connector 5900, the outer housing5901 comprises a pair of alignment keys 5905, 5906 on each of a pair ofopposite sides or ends (e.g., top and bottom) of the outer housing 5901.In general, each alignment key 5905, 5906 is configured to be receivedin a respective alignment recess of an adapter, as will be described infurther detail below. Each of the illustrated alignment keys 5905, 5906is generally in line with a respective hook recess 5961, 5963 (along awidth WC (FIG. 59B) of the connector. For purposes of this disclosure, ahook recess is in line with a hook recess along the width of theconnector when it at least partially overlaps the hook recess along thewidth of the connector. To prevent the connector 5300 from beingconnected in a reverse-polarity orientation, in one or more embodiments,the upper and lower alignment keys 5905, 5906 are offset from oneanother along a width WC of the connector. In certain embodiments, theupper and lower alignment keys 5905, 5906 differ in one or more of size,shape, and location to prevent being connected in a reverse-polarityorientation. In the illustrated embodiment, the width WC is a seconddimension perpendicular to the dimension along which sides of theconnector on which the alignment keys are formed are spaced apart fromone another, e.g., the height HC.

Referring to FIG. 64, the connectors 5900 are sized and arranged suchthat four of the connectors can be arranged in side-by-side relationshipwithin a QFSP footprint FQFSP. Similarly, two of the connectors 5900 canbe arranged in side-by-side relationship within an SFP footprintF_(FSP), as shown in FIG. 65. Referring to FIG. 66, four of a connector6600 having an MT-type ferrule 6620 in place of the LC ferrules 5920 ofthe connector 5900 can likewise be arranged in side-by-side relationshipwithin a Q_(FSP) footprint F_(QFSP). Similarly, two of the connectors6600 can be arranged in side-by-side relationship within an SFPfootprint F_(FSP), as shown in FIG. 65.

Referring to FIGS. 60A-60C, in one embodiment, an adapter 6000 for asimplex SC connector comprises a housing 6004 defining one or morereceptacles 6002. In the illustrated embodiment, at each receptacle6002, the housing 6004 comprises first and second open-ended alignmentslots 6006, 6008 extending through an entire thickness of each of anopposite pair of side walls 6004A of the housing. Each slot 6006, 6008is configured to receive an alignment key of an SC connector therein.Placing slots 6006, 6008 on opposite side walls of the adapter housing6004 facilitates placement of the connector in the receptacle 6002 ineither of two opposite orientations. Opposing hook arms 6010 arereceived in the housing to retain the connector therein. The hook arms6008 are configured to deflect toward side walls 6004B orientedperpendicular to the side walls 6004A at which the open-ended slots6006, 6008 are formed.

Referring to FIGS. 61A-61D, an exemplary embodiment of an adapter isgenerally indicated at reference number 6100. In one or more aspects ofthe present disclosure, the adapter 6100 comprises at least onereceptacle 6102, 6103 configured to operatively receive at least oneoptical connector (e.g., connector 5300) for making a connection withthe at least one optical connector. In an exemplary embodiment, theadapter 6100 includes first and second receptacles 6102, 6103 atopposite ends of the adapter that are aligned for making an opticalconnection between one or more pairs of optical connectors. In anotherembodiment, the adapter comprises a transceiver having a singlereceptacle at one end and optical or opto-electrical components atanother end to which a connector is connected when installed in thereceptacle. In the illustrated embodiment, the adapter 6100 comprisesfour-bay receptacles 6102, 6103, each configured for receiving a fourconnectors therein in side-by-side relation. But in other embodiments,the adapter could comprise multi-bay adapters configured for receivingmultiple connectors therein as will be described in further detailbelow.

The adapter 6100 comprises a housing 6104 that defines each receptacle6102, 6103. In the illustrated embodiment, the adapter housing 6104 hasa top wall 6104A and a bottom wall 6104B (broadly, first and secondsides) that are spaced apart along a height HA (broadly, a firstdimension) of the adapter 6102, opposite first and second side walls6104C, 6104D that are spaced apart along a width WA (broadly, a seconddimension perpendicular to the first dimension) of the adapter, andopposite ends spaced apart along a length LA (broadly, a third dimensionperpendicular to the first and second dimensions) of the adapter. Thetop and bottom walls 6104A, 6104B define the tops and bottoms of thereceptacles 6102, 6103 and the side walls 6104C, 6104D define theopposite sides of the receptacles.

For each bay of the adapter 6100, one receptacle hook 6108 is receivedin the adapter. Generally, each hook 6108 is configured to retain oneconnector in at least one of the receptacles 6102, 6103. In one or moreembodiments, a single hook member 6108 is configured to retain oneconnector 5300 in each receptacle 6102, 6103. But in other embodiments,separate hook members could be used in each receptacle. In FIGS.61A-61D, four receptacle hooks 6108 are received in the adapter becausethe receptacles 6102, 6103 are four-bay receptacles. But in otherembodiments, other numbers of hooks can be received in each receptacle.

Referring to FIG. 61C, in each receptacle, the hook 6108 comprises atleast one hook arm 6110, 6111, 6112, 6113 that is configured toresiliently deflect as the respective optical connector is inserted intothe respective receptacle 6102, 6103 and to resiliently rebound afterthe respective optical connector is inserted into the receptacle wherebythe hook arm engages the connector to retain the connector in therespective receptacle (e.g., catch portions of the hook arms arereceived in the connector recesses 5361, 5363). The housing 6104 issuitably formed to accommodate each hook arm being deflected as theoptical connector is inserted into the receptacle.

In the illustrated embodiment, the hook 6108 comprises an upper hook arm6110, 6111 and a lower hook arm 6112, 6113 in each receptacle 6102,6103. A middle wall 6114 located between the opposite pairs of hook arms6110, 6112, 6111, 6113 along the length of the hook 6108 extends betweenthe upper and lower hook arms along the height HA of the adapter 6100and holds each upper hook arm in spaced apart relationship with theopposing lower hook arm. In the illustrated embodiment, the middle wall6114 is partially defined by the hook 6108 and partially defined by theadapter housing 6104 as explained with respect to above-describedadapter embodiments. FIG. 61C further depicts adapter housing hook 6132secured behind wall portion 6104 e within upper recess 6120.

Each of the illustrated hooks 6108 defines a first and second opening6116 (FIG. 61B) located between the upper and lower hook arms 6110,6111, 6112 6113. The openings 6116 extend through the middle wall 6114for passing optical signals to and/or from the first receptacle 6102 andthe second receptacle 6103. In the illustrated embodiment, each opening6116 retains a ferrule alignment sleeve 6118 for LC ferrules. Hence, theillustrated adapter 6100 is configured so that optical signals arepassable through the openings 6116 from and/or to an LC connector. Inanother embodiment, the connector could be configured so that opticalsignals are passable from and/or to an MT-type connector, e.g., theMT-type connector shown in FIGS. 18A and 18B or the MT-type connectors6610 shown in FIGS. 66 and 67. In still another embodiment, theconnector could be configured so that optical signals are passable fromand/or to a lens-type ferrule connector as shown in FIG. 18C. Further,it will be understood that the adapter could have other numbers andsizes of openings between the hook members for passing optical signalsto, from, and/or between connectors.

As introduced above, the upper and lower hook arms 6110, 6112, 6111,6113 in each receptacle 6102, 6103 are configured to deflect outwardlytoward the top and bottom walls 6104A, 6104B of the adapter housing 6104as the connector 5300 is inserted. The top wall 6104A of the adapter isformed accommodate the deflection of the upper hook arms 6110, 6111 andthe bottom wall 6104B of the adapter is formed to accommodate thedeflection of the lower hook arms 6112, 6113. Referring to FIG. 61C, ateach receptacle 6102, 6103, the top wall of the housing 6104 has anupper recess (e.g., gap or bounded space) 6120, 6121 formed into aninterior surface thereof to accommodate the deflection of the respectiveupper hook arms 6110, 6111 and the bottom wall of the adapter housinghas a lower recess 6122, 6123 formed into an interior surface thereof toaccommodate the deflection of the respective lower hook arms 6112, 6113.The upper and lower recesses 6120, 6121, 6122, 6123 receive portions ofthe respective upper and lower hook arms 6110, 6112, 6111, 6113 upondeflection.

Suitably an outer web portion 6124, 6125 of the top wall 6104A of theadapter housing 6104 covers at least a portion (e.g., more than half orall) of the respective upper recess 6120, 6121, and similarly an outerweb portion 6126, 6127 of the adapter housing covers at least a portion(e.g., more than half or all) of the respective lower recess 6122, 6123.In the illustrated embodiment, each recess is defined by alongitudinally extending outer end surface, which is formed by therespective web portion 6124, 6125, 6126, 6127. Each recess 6120, 6121,6122, 6123 is defined by a longitudinally extending upper or lowersurface (formed by the respective web portion 6124, 6125, 6126, 6127).As shown in FIG. 61D, each illustrated recess 6120, 6121, 6122, 6123spans the four hooks 6108 along the width WA of the adapter 6100.Referring to FIG. 61C, each of the recesses 6120, 6121, 6122, 6123 has aclosed outer longitudinal end 6120A, 6121A, 6122A, 6123A that extendsinward along the height HA from the respective web 6124, 6125, 6126.Each of the illustrated recesses 6120, 6121, 6122, 6123 has asubstantially constant thickness TR.

At each receptacle, 6102, 6103, the illustrated adapter housing 6104comprises, for each connector that is receivable therein, an upperalignment recess 6130, 6131 formed on an interior surface of the topwall 6104A and a lower alignment recess 6132, 6133 formed on an interiorsurface of the bottom wall 6104B. In general, the alignment recesses6130, 6131, 6132, 6133 are configured to receive the upper and loweralignment keys of a connector when the connector is installed in thereceptacle 6102, 6103. It will be understood that when connectors havingonly a single alignment key are used, one of the upper or lower alimentkey recesses can be omitted from the adapter housing. As shown in FIG.61C, each alignment key recesses 6130, 6131, 6132, 6133 is spaced apartoutwardly from the respective hook recess 6120, 6121, 6122, 6123 alongthe length LA of the adapter 6100. Suitably, a middle portion of therespective one of the top and bottom walls 6104A, 6104B is locatedbetween the alignment key recess 6132, 6133 and the respective hookrecess 6120, 6121, 6122, 6123. The housing wall 6104A, 6104B has itsmaximum wall thickness TW along this middle portion.

Suitably each upper alignment recess 6130, 6131 is in line with therespective upper hook arm 6120, 6121 along the width WA (FIG. 61D) ofthe adapter 6100, and each lower alignment recess 6132, 6133 isgenerally aligned with the respective lower hook arm 6122, 6123 alongthe width of the adapter. For purposes of this disclosure, an alignmentrecess is in line with the respective hook arm when the alignment recessat least partially overlaps the hook arm along the width of the adapter.The alignment recesses 6130, 6131, 6132, 6133 are located adjacent theoutboard ends of the adapter housing 6104 and are open-ended so that thealignment keys on a connector slot into the alignment key recesses asthe connector is inserted into the respective receptacle 6102, 6103. Asshown in FIG. 62, to prevent reverse-polarity installation of theconnectors 5900, in one or more embodiments of an adapter 6200, eachupper alignment key recess 6230 can be offset from the correspondinglower alignment key recess 6232 along the width WA of the housing 6204.In addition or in the alternative, the upper alignment key recess 6230can have one or both of a different size and shape than the loweralignment key recess 6232.

Referring still to FIG. 62, in one embodiment, the adapter 6200 isconfigured to receive four connectors 5900 in side-by-side relation ineach receptacle 6102, 6103. The adapter 6200 thus includes four hooks(not shown). Suitably, the adapter 6200 is free of any wall locatedbetween any of the plurality of hooks along the width WA. Omitting wallsbetween the hooks 6108 minimizes the cross-sectional dimensions of theadapter. As indicated in the dimensions for adapter width WA and adapterheight HA in FIG. 62, in one or more embodiments, the housing perimeterof the adapter housing 6204 is generally accommodated in a quad smallform-factor pluggable (QSFP) transceiver footprint F_(QSFP) (FIG. 64).For purposes of this disclosure, an adapter is “generally accommodated”in a transceiver footprint when the height and width of the adapter areno more than about 0.5 mm greater than the corresponding dimensions ofthe standard transceiver footprint. In the illustrated embodiment, theheight and width of the adapter 6200 are less than or equal to thecorresponding dimensions of the standard QSFP transceiver footprintF_(QSFP). As shown in FIG. 68, the adapter 6800, which is configured toreceive four MT-type-connectors 6802 in each receptacle, also has ahousing perimeter that is generally accommodated in a quad smallform-factor pluggable (QSFP) transceiver footprint F_(QSFP). Forexample, the height and width of the adapter 6800 are less than thecorresponding dimensions of the standard QSFP transceiver footprintF_(QSFP).

As indicated in the dimensions in FIG. 63, the housing perimeter of ahousing 6304 of an adapter 6300 comprising two-bay receptacles that arefree of walls between hook members 6308 is generally accommodated in asmall form-factor pluggable transceiver footprint F_(SFP) (FIG. 65). Thesum of the height and width of the adapter 6300 is less than or equal tothe sum of the corresponding dimensions of the standard SFP transceiverfootprint F_(SFP). As shown in FIG. 69, the adapter 6900, which isconfigured to receive two MT-type connectors 6802 in each receptacle,also has a housing perimeter that is generally accommodated in a smallform-factor pluggable (SFP) transceiver footprint F_(SFP). In theillustrated embodiments, the sum of the height and width of the adapter6900 is less than the sum of the corresponding dimensions of the smallform-factor pluggable transceiver footprint F_(SFP).

Referring to FIGS. 70A-70B, in one or more embodiments, an adapter 7000comprises an adapter housing 7002 and a hook 7004 that is integrally andunitarily formed with the adapter housing, from one piece of moldedmaterial. In the illustrated embodiment, the hook 7004 comprises fourpairs of opposing hook arms 7006, 7008 that extend from a middle wall7010 into a receptacle 7012 defined by the adapter housing. As above,each pair of hook arms 7006, 7008 is configured to retain a connector inthe receptacle 7012. Further each pair of hook arms 7006, 7008 isconfigured to resiliently deflect outwardly when the connector isinserted into the receptacle and resiliently rebound inwardly to retainthe connector in the receptacle.

The middle wall 7010 includes upper and lower webs 7010A, 7010B thatintegrally connect the middle wall to the top and bottom of the housing7002. In the illustrated embodiment, each of the upper and lower webs7010A, 7010B has a laterally extending middle portion that is spacedapart vertically from the respective one of the top and bottom wall ofthe housing 7002. Lateral end portions of the upper and lower webs7010A, 7101B extend vertically outward from the middle portion to therespective one of the top and bottom wall. The upper hook arms 7006 areintegrally connected to the upper web 7010A and extend longitudinallyfrom the upper web 7010A into the receptacle 7012. Similarly, the lowerhook arms 7008 are integrally connected to the lower web 7010B andextend longitudinally from the lower web into the receptacle 7012.

The middle wall 7010 also includes a plurality of struts 7010C thatextend vertically between the upper and lower webs 7010A, 7010B andsupport the upper and lower webs in spaced apart relationship. Thestruts 7010C are laterally spaced apart along a width of the adapterhousing 7002 and define openings 7014 therebetween. Each opening 7014 isaligned with a respective pair of hook arms 7006, 7008 along the widthof the adapter housing 7002. Further, each opening 7014 is configured toreceive an alignment sleeve or an alignment sleeve holder therein (notshown). The alignment sleeve or alignment sleeve holder (not shown) isconfigured to align a ferrule of a connector retained by the respectivepair of hook arms 7006, 7008 for making an optical connection.

The housing 7002 of the adapter 7000 comprises an upper alignment keyrecess 7016 and a lower alignment key recess 7018 for receiving a pairof alignment keys of a connector as described above.

Although the illustrated adapter 7000 comprises a hook 7004 formedintegrally with the housing 7002 that defines four pairs of hook arms7006, 7008, other adapters with integrally formed hooks can have othernumbers of pairs of hook arms. For example, referring to FIGS. 71A-71B,in one or more embodiments, an adapter 7100 comprises a housing 7102 anda hook 7104 having two pairs of opposing hook arms 7106, 7108 that isintegrally and unitarily formed with the adapter housing, from one pieceof molded material. Except for the difference in number of pairs ofopposing hook arms, the hook 7104 has the same basic configuration asthe hook 7004. In other embodiments, adapters comprising integrallyformed hooks can have still other numbers of opposing pairs of hookarms.

In the above detailed description, reference is made to the accompanyingdrawings, which form a part hereof. In the drawings, similar symbolstypically identify similar components, unless context dictatesotherwise. The illustrative embodiments described in the detaileddescription, drawings, and claims are not meant to be limiting. Otherembodiments may be used, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presentedherein. It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in theFigures, can be arranged, substituted, combined, separated, and designedin a wide variety of different configurations, all of which areexplicitly contemplated herein.

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its spirit and scope, as will be apparentto those skilled in the art. Functionally equivalent methods andapparatuses within the scope of the disclosure, in addition to thoseenumerated herein, will be apparent to those skilled in the art from theforegoing descriptions. Such modifications and variations are intendedto fall within the scope of the appended claims. The present disclosureis to be limited only by the terms of the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isto be understood that this disclosure is not limited to particularmethods, reagents, compounds, compositions or biological systems, whichcan, of course, vary. It is also to be understood that the terminologyused herein is for the purpose of describing particular embodimentsonly, and is not intended to be limiting.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (for example, bodiesof the appended claims) are generally intended as “open” terms (forexample, the term “including” should be interpreted as “including butnot limited to,” the term “having” should be interpreted as “having atleast,” the term “includes” should be interpreted as “includes but isnot limited to,” et cetera). While various compositions, methods, anddevices are described in terms of “comprising” various components orsteps (interpreted as meaning “including, but not limited to”), thecompositions, methods, and devices can also “consist essentially of” or“consist of” the various components and steps, and such terminologyshould be interpreted as defining essentially closed-member groups. Itwill be further understood by those within the art that if a specificnumber of an introduced claim recitation is intended, such an intentwill be explicitly recited in the claim, and in the absence of suchrecitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (for example, “a” and/or “an” should be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould be interpreted to mean at least the recited number (for example,the bare recitation of “two recitations,” without other modifiers, meansat least two recitations, or two or more recitations). Furthermore, inthose instances where a convention analogous to “at least one of A, B,and C, et cetera” is used, in general such a construction is intended inthe sense one having skill in the art would understand the convention(for example, a system having at least one of A, B, and C″ would includebut not be limited to systems that have A alone, B alone, C alone, A andB together, A and C together, B and C together, and/or A, B, and Ctogether, et cetera). In those instances where a convention analogous to“at least one of A, B, or C, et cetera” is used, in general such aconstruction is intended in the sense one having skill in the art wouldunderstand the convention (for example, “a system having at least one ofA, B, or C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, et cetera). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, et cetera As a non-limiting example, each range discussed hereincan be readily broken down into a lower third, middle third and upperthird, et cetera As will also be understood by one skilled in the artall language such as “up to,” “at least,” and the like include thenumber recited and refer to ranges which can be subsequently broken downinto subranges as discussed above. Finally, as will be understood by oneskilled in the art, a range includes each individual member. Thus, forexample, a group having 1-3 cells refers to groups having 1, 2, or 3cells. Similarly, a group having 1-5 cells refers to groups having 1, 2,3, 4, or 5 cells, and so forth.

Various of the above-disclosed and other features and functions, oralternatives thereof, may be combined into many other different systemsor applications. Various presently unforeseen or unanticipatedalternatives, modifications, variations or improvements therein may besubsequently made by those skilled in the art, each of which is alsointended to be encompassed by the disclosed embodiments.

1. An optical connector comprising: a housing configured to be removablyinserted into a receptacle of an adapter, wherein the adapter comprisesa receptacle hook received in the receptacle and comprising a first hookarm and a second hook arm in opposing relation with the first hook arm;and at least one ferrule received in the housing; wherein the opticalconnector has first and second recesses on opposite sides of the opticalconnector; and wherein the optical connector is configured so that whenthe optical connector is received in the receptacle of the adapter, thefirst recess receives a portion the first hook arm and the second recessreceives a portion of the second hook arm to retain the opticalconnector in the receptacle.
 2. An optical connector as set forth inclaim 1, further comprising a plurality of optical fibers supported inthe housing between the first and second recesses.
 3. An opticalconnector comprising: a housing configured to be removably inserted intoa receptacle of an adapter; and a plurality of optical fibers supportedin the housing; wherein the optical connector has first and secondrecesses on opposite sides of the optical connector; and wherein theplurality of optical fibers are located between the first and secondrecesses.
 4. An optical connector as set forth in claim 3, furthercomprising at least two LC ferrules supported in the housing between thefirst and second recesses.
 5. An optical connector as set forth in claim3, further comprising an MT-type ferrule supported in the housingbetween the first and second recesses.
 6. An optical connectorcomprising: an outer housing configured to be removably inserted into areceptacle of an adapter, the outer housing having an opening extendingthrough the outer housing along a longitudinal axis; at least oneoptical fiber ferrule; and at least one inner front body received in theopening of the outer housing, each inner front body having an interiorin which the inner front body is configured to support the at least oneoptical fiber ferrule, each inner front body comprising first and secondlongitudinal wall portions extending along the longitudinal axis onopposite ends of the interior, each inner front body having opensidewalls between the first and second wall portions on opposite sidesof the interior.
 7. In an optical connector holding two or more opticalfibers having an outer body, an inner front body accommodating the twoor more optical fibers, one or more ferrule springs for urging theoptical ferrules toward a mating connection, and a back body forsupporting the ferrule springs, the improvement comprising configuringthe outer body and the inner front body such that two optical connectorshaving four or more optical fibers are accommodated in a smallform-factor pluggable (SFP) transceiver footprint.
 8. In an opticalconnector holding two or more optical fibers having an outer body, aninner front body accommodating the two or more optical fibers, one ormore ferrule springs for urging the optical ferrules toward a matingconnection, and a back body for supporting the ferrule springs, theimprovement comprising configuring the outer body and the inner frontbody such that at least four optical connectors having a total of eightor more optical fibers are accommodated in a quad small form-factorpluggable (QSFP) transceiver footprint.